International Trade Centre UNCTAD/GATT. (1975). Trade information classification. The Centre.
Cita Chicago (17th ed.)International Trade Centre UNCTAD/GATT. Trade Information Classification. Geneva: The Centre, 1975.
Cita MLA (9th ed.)International Trade Centre UNCTAD/GATT. Trade Information Classification. The Centre, 1975.
Atenció: Aquestes cites poden no estar 100% correctes.